1. Field of the Invention
The present invention generally relates to communications systems and, more particularly, to communications systems which communicate using the Internet Protocol.
2. Background of the Invention
The Internet Protocol (IP) is a network layer protocol that provides unique global computer addressing on a packet switched communications inter-network, such as the Internet, thereby enabling two communication devices communicating over the inter-network to uniquely identify one another. Version 4 of the Internet Protocol (IPv4) is the fourth iteration of Internet Protocol, but is the first version of the protocol to be widely deployed. Apart from IPv6, IPv4 is the only network layer protocol used on the Internet.
IPv4 uses 32-bit (4-byte) addresses, which limits the number of possible unique IP addresses to approximately 4.3 billion. With the current global population approaching 7 billion people, the IPv4 address space is not adequate to assign a unique IP address to every living person. Thus, as use of the Internet continues to expand throughout the world, the number of IP addresses available using IPv4 soon will be consumed and an IPv4 address shortage appears to be inevitable.
The address limitation inherent in IPv4 has helped stimulate the push towards IPv6, which uses 128-bit (16-byte) addresses. This provides enough room for approximately 3.4×1038 unique addresses, which should provide adequate address space for the foreseeable future.
The migration from IPv4 to IPv6 is multifaceted and non-trivial, however. Indeed, for some time IPv4 and IPv6 will co-exist and devices configured to communicate with one another using IPv6 may find themselves separated by infrastructure that exclusively supports IPv4. Thus, there exists a need to enable IPv6 devices to communicate over an IPv4 network. Some solutions have been proposed to address this need, but such solutions are inefficient, insecure, or do not adequately accommodate the ever expanding mobile communications environment.